It's pretty obviously a dumb hoax. The supposed freelancer has a client account and the supposed email address is a spoof.

Anyone can go into contact forms on websites and add whatever invented / imaginary email address they like as the sender, or even the email address of any given real person.

That does not mean the action originates from the domain in question, let alone the person.

It would be a pretty dumb thing to do if a real freelancer really did try to get hired that way, so I'd assume this to be some idiotic prankster, maybe one of the endless freelancers Upwork rejects or kicks out.